a$.$ Explain the following i$.$ Direct Memory Access. $[3]$ ii$.$ Polling. is a technigue used iii. Priority Interrupt. $33$ b$.$ Distinguish synchronous bus and as'n :hronous bus. $8$ c$.$ Discuss the operations of any two in x devices. Question $5$ a$.$ Suppose you own a computer that exhibits the following properties on the programs that run: The pipeline can accept a new instruction every cycle The cache can provide data every cycle The instruction cache miss rate is $2\mathrm{.}5\%$ THE data cache miss rate is $3\mathrm{.}5\%30\%$ of instructions are memor instructions Cache miss penalty is $80$ cyc e: You have decided to purchase a new computer and for the budget you can either purchase a machine with a processor and cache : s twice as fast as your current one or get a machine with a processor an